scholarly journals Temporal discounting correlates with directed exploration but not with random exploration

2019 ◽  
Author(s):  
Hashem Sadeghiyeh ◽  
Siyu Wang ◽  
Maxwell R. Alberhasky ◽  
Hannah M. Kyllo ◽  
Amitai Shenhav ◽  
...  

AbstractThe explore-exploit dilemma describes the trade off that occurs any time we must choose between exploring unknown options and exploiting options we know well. Implicit in this trade off is how we value future rewards — exploiting is usually better in the short term, but in the longer term the benefits of exploration can be huge. Thus, in theory there should be a tight connection between how much people value future rewards, i.e. how much they discount future rewards relative to immediate rewards, and how likely they are to explore, with less ‘temporal discounting’ associated with more exploration. By measuring individual differences in temporal discounting and correlating them with explore-exploit behavior, we tested whether this theoretical prediction holds in practice. We used the 27-item Delay-Discounting Questionnaire to estimate temporal discounting and the Horizon Task to quantify two strategies of explore-exploit behavior: directed exploration, where information drives exploration by choice, and random exploration, where behavioral variability drives exploration by chance. We find a clear correlation between temporal discounting and directed exploration, with more temporal discounting leading to less directed exploration. Conversely, we find no relationship between temporal discounting and random exploration. Unexpectedly, we find that the relationship with directed exploration appears to be driven by a correlation between temporal discounting and uncertainty seeking at short time horizons, rather than information seeking at long horizons. Taken together our results suggest a nuanced relationship between temporal discounting and explore-exploit behavior that may be mediated by multiple factors.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Peter Lenart ◽  
Julie Bienertová-Vašků ◽  
Luděk Berec

Abstract Background The pace of aging varies considerably in nature. The best-known explanation of the evolution of specific rates of aging is the Williams’ hypothesis suggesting that the aging rate should correlate with the level of extrinsic mortality. However, the current evidence is inconclusive with various examples where the Williams' hypothesis seems to be correct and where it doesn’t. Here we explore the relationship between extrinsic mortality and aging rate by developing a simulation model of the evolution of aging rate in prey subject to predation. Results Our results suggest that more intense predation leads to the evolution of faster pace of aging in prey. However, this effect slowly vanishes when the predator diet breadth is allowed to evolve, too. Furthermore, in our model, the evolution of a specific aging rate is driven mainly by a single parameter, the strength of a trade-off between aging and fecundity. Indeed, in the absence of this trade-off the evolutionary impacts of predation on the prey aging rate appear random. Conclusions We show that the William’s hypothesis appears valid when there is a trade-off between aging and fecundity and predators and prey do not coevolve. However, we also show that when the prey and predators coevolve or if there is no trade-off between aging and fecundity the William`s hypothesis is no longer applicable.


Author(s):  
Ali Abedzadeh ◽  
Abdolhadi Daneshpour ◽  
Maryam Ostadi

Humanity settlement are formed as a result of decisions and actions of different people and become as a form of an identity of integrity. So urban form is influenced by desires, values, beliefs, and human activities, so the study of urban form is the study of its constituent human values and expression of physical aspects of their lifestyles. Before contemporary periods, urban form in Iran, continuity based on former patterns of changes, which was gradual, but after the beginning of the influence of west, one of the most important challenges of urban form in Iran is in the form of short-term changes. Changes occur in a cycle of destruction and construction. This paper use the way of content analysis investigate to texts, document to study form and typo-morphology of residential environment in the city of Mashhad. In the periods of one hundred years shows there is a direct and significant relationship between changes of Iranian lifestyle and metamorphosis of urban form, so that by sequential developments of Iranian lifestyle in a short time, the urban form is responded and metamorphosed and again is created in a new form.


2007 ◽  
Vol 13 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Vidmantas Jokūbaitis

Long and short‐term (accelerated with simulation of pressure developed by compressed rust) experimental investigations were accomplished. It was investigated in long‐term tests the relationship between the width of the longitudinal cracks on the concrete surface and close to the reinforcement, and relation between these widths and corrosion‐induced damages in the reinforcement; parameters of these relationships were established. In short‐time investigations it was tried to clarify the influence of transverse reinforcement and opened normal cracks on the nature of longitudinal cracks propagation. It has been determined that the character and the rate of propagation of the longitudinal cracks depend on distribution of transverse reinforcement and normal cracks along a member.


2019 ◽  
Vol 15 (1) ◽  
pp. 37-48
Author(s):  
Nahid Kalbasi Anaraki

The Phillips curve on the trade-off between inflation and unemployment has been debated among economists for more than decades. Several studies have found that Phillips curve is dead in advanced economies and does not exist. Among others, Friedman (1968) stated that Phillips curve does not exist in the long-run because the relationship between inflation and unemployment is a temporary and short-term. On the contrary, Fuhrer (1995) found that Phillips curve is still alive in the United Kingdom; and Malinov and Sommers (1997) found that Phillips curve is still alive and stable in several OECD countries. This paper attempts to investigate whether a long-run Philips Curve exists in China. Using data for the period of 1987-2016 the estimated results of this study indicate that the Phillips curve, which existed during the late 1980s through 2000 in China has been gradually transformed to an almost vertical curve since 2000s, with a correlation of 0.8, indicating the importance of other policy variables including monetary policy and exchange rate regimes.


2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Nazeer Joseph ◽  
Carl Marnewick

Information systems (IS) project success has been a perennial bane of many researchers. Although there are short, medium and long-term dimensions to success, the reality is that they are inseparably linked. Time plays a significant role as a stakeholder, such as a project manager who has short-term interests. In contrast, a business executive has long-term interests for the organisation as a whole. Project success is arguably a continuum where each dimension plays a role in realising long-term benefits for the organisation. This research investigates IS projects specifically to understand the argued correlation between short, medium and long-term project success dimensions. A total of 612 valid responses were collected through an online questionnaire. Quantitative analysis through PLS-SEM was conducted to reveal the correlation between success dimensions. The overall implication is that short-term IS project success does not directly correlate with long-term IS project success. However, there is a clear correlation between the time phases of IS project success. This research shows medium-term success mediates the relationship and correlation of short and long-term success. While literature acknowledges the relationship literature, this research confirms this notion and proves a significant correlation between each IS project success dimension over time.


Author(s):  
Shivananda B Nayak ◽  
Dharindra Sawh ◽  
Brandon Scott ◽  
Vestra Sears ◽  
Kareshma Seebalack ◽  
...  

Purpose: i) To determine the relationship between the cardiac biomarkers ST2 and NT-proBNP with ejection fraction (EF) in heart failure (HF) patients. ii) Assess whether a superiority existed between the aforementioned cardiac markers in diagnosing the HF with reduced EF. iii) Determine the efficacy of both biomarkers in predicting a 30-day cardiovascular event and rehospitalization in patients with HF with reduced EF iv) To assess the influence of age, gender, BMI, anaemia and renal failure on the ST2 and NT-proBNP levels. Design and Methods: A prospective double-blind study was conducted to obtain data from a sample of 64 cardiology patients. A blood sample was collected to test for ST2 and NT-proBNP. An echocardiogram (to obtain EF value), electrocardiogram and questionnaire were also obtained. Results: Of the 64 patients enrolled, 59.4% of the population had an EF less than 40%. At the end of the 30- day period, 7 patients were warded, 37 were not warded, one died and 17 were non respondent. Both biomarkers were efficacious at diagnosing HF with a reduced EF. However, neither of them were efficacious in predicting 30-day rehospitalization. The mean NT-proBNP values being: not rehospitalized (2114.7486) and 30 day rehospitalization (1008.42860) and the mean ST2 values being: not rehospitalized (336.1975), and 30-day rehospitalization. (281.9657). Conclusion: Neither ST2 or NT-proBNP was efficacious in predicting the short- term prognosis in HF with reduced EF. Both however were successful at confirming the diagnosis of HF in HF patients with reduced EF.


2020 ◽  
Vol 35 (3) ◽  
Author(s):  
Tayyaba Gul Malik ◽  
Hina Nadeem ◽  
Eiman Ayesha ◽  
Rabail Alam

Objective: To study the effect of short-term use of oral contraceptive pills on intra-ocular pressures of women of childbearing age.   Methods: It was a comparative observational study, conducted at Arif memorial teaching hospital and Allied hospital Faisalabad for a period of six months. Hundred female subjects were divided into two groups of 50 each. Group A, included females, who had been taking oral contraceptive pills (OCP) for more than 6 months and less than 36 months. Group B, included 50 age-matched controls, who had never used OCP. Ophthalmic and systemic history was taken. Careful Slit lamp examination was performed and intraocular pressures (IOP) were measured using Goldman Applanation tonometer. Fundus examination was done to rule out any posterior segment disease. After collection of data, we analyzed and compared the intra ocular pressures between the two groups by using ANOVA in SPSS version 21.   Results: Average duration of using OCP was 14.9 months. There was no significant difference of Cup to Disc ratios between the two groups (p= 0.109). However, significant difference was noted between the IOP of OCP group and controls. (p=0.000). Conclusion: OCP significantly increase IOP even when used for short time period.


Author(s):  
Claudius Härpfer

In recent times we find many plebiscitary acts that seek to democratically legitimize political processes in any direction. They have in common that they interrupt the normal routine of representative democracies to a certain degree and create an extra-daily state of affairs, which entails not only direct but also indirect consequences. The text attempts to systematize some of these mechanisms from a Weberian perspective using Brexit as an example. After a brief overview of Weber’s short-term politically inspired statements on plebiscitary democracy, the text systematizes Weber’s understanding of the state as a bureaucratic apparatus that requires any kind of leader to be controlled. Subsequently, the text discusses the relationship between domination, legality, and rationality in order to finally point out the danger of erosion of truth and legality through the emergence of competing consensus communities in the face of competing conceptions of order.


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